House Republicans said Monday they will call for an investigation into whether Rep. William Jefferson "should be expelled from the House for conduct that brings dishonor to the institution" in the wake of a 16-count federal indictment that includes charges of racketeering, money-laundering and soliciting more than $400,000 in bribes.

But with a history of only two members having been expelled in the past 140 years -- both after having been convicted -- and a 1967 U.S. Supreme Court decision that overruled a vote to unseat Rep. Adam Clayton Powell, D-N.Y., based on allegations, experts say it is unlikely that the House will try to oust Jefferson before he gets his day in court.

A trial could come fairly quickly. District Court Judge T.S. Ellis III, who has presided over the guilty pleas of two Jefferson associates, is now on senior status, which means he doesn't have as large a caseload as he did previously, freeing him to schedule the case, perhaps as early as September or October.

Jefferson is due in federal court in Virginia on Friday to enter what is a pro-forma innocent plea to the 16 charges.

Still, House Republican Leader John Boehner, R-Ohio, said he will ask as early as today for the Ethics Committee to begin an investigation and also will seek a vote on a GOP resolution to strip Jefferson of his only committee seat.

Boehner said that if Democrats "are serious about holding all lawmakers to the highest standards of ethical conduct," they will support the Republican effort to remove him from the Small Business Committee.

House Speaker Nancy Pelosi, D-Calif., who last year led the successful effort to remove Jefferson from the more powerful House Ways and Means Committee, didn't comment on Boehner's request. She said that Jefferson, "just like any other citizen must be considered innocent until proven guilty," but also said that "if these charges are proven true, they constitute an egregious and unacceptable abuse of public trust and power."

Pelosi said last year that the Ways and Means Committee was different than most House committees because it had so much sway over legislation -- with jurisdiction on almost every key issue before the House. Therefore, membership on such a panel should be deemed a privilege and membership could be denied quite justifiably to any member under suspicion for improper conduct. Pelosi's action against Jefferson came after federal prosecutors revealed they had found $90,000 in the freezer of the congressman's Washington D.C. home.

Jefferson had hoped to gain a seat on the Homeland Security Committee, in addition to his Small Business slot. But aides to Pelosi said that the chances of that happening now are virtually non-existent.

The Homeland Security assignment, which Jefferson requested because it oversees key issues related to hurricane recovery, was already in doubt because of Republican opposition and a desire by Democratic leaders not to force their vulnerable members into a politically risky vote.

The indictment is likely to weaken Jefferson's already reduced clout, said Thomas Mann, a senior fellow at the Brookings Institution.

"I think most Democrats in the House assume Jefferson is gone -- it's just a matter of time," Mann said. "An indictment will take the pressure off the Black Caucus to defend his rights to prime committee assignments and lead to his greater isolation in the House."

If he's found guilty, Jefferson would almost certainly be expelled by a vote of his House colleagues, unless he voluntarily resigned.

Two members of Congress have been voted out of their seats since the Civil War. The most recent was Rep. Jim Traficant, D-Ohio, ousted by a 420-1 vote in 2002, after an Ohio jury found him guilty of taking bribes from businesses and kickbacks of salaries from his congressional staffs. In 1980, Rep., Michael Myers, D-Penn., was expelled after his conviction for taking bribes as part of an FBI sting operation known as Abscam.

Some members, after being convicted or pleading guilty to a crime, chose to resign rather than be subjected to a formal ouster vote by their colleagues. Among them: Rep. Duke Cunningham, R-Calif., who pled guilty last year to accepting bribes in return for getting appropriations for defense contractors and Bob Ney, R-Ohio, who admitted last year to doing legislative favors for disgraced lobbyist Jack Abramoff in return for gifts that included trips and tickets to sporting events.

Larry Sabato, director of the Institute of Politics at the University of Virginia, said that given that Jefferson has been under investigation for over two years, and with the government disclosing more than a year ago that it found $90,000 in his freezer, he isn't "going to be hurt personally much more than he already is."

But Julian Zelizer, a Boston University history professor an co-editor of "Politics and Society in 20th Century America," predicts that some Democrats will work behind the scenes to press Jefferson to resign. "With the next budget battle coming in September, public attention squarely against the administration, the Democrats can't afford to have the 'culture of corruption' issue back -- this time with them as the targets."

Melanie Sloan, executive director of Citizens for Responsibility and Ethics in Washington, was one of the first to call on Jefferson to resign.

"At a time when the citizens for Louisiana face so many serious challenges, they deserve a member of Congress dedicated to serving their needs rather than focused on his own criminal defense," Sloan said.

Last month, Rep. James Sensenbrenner, R-Wis., questioned why the Justice Department had taken so long to bring the case against the New Orleans Democrat. The investigation began in March, 2005.

Chuck Rosenberg, the U.S. attorney for Northern, Virginia, where the case was brought, said that the indictments were sought when prosecutors believed they had the evidence to proceed.

"Frankly, we don't give a damn about politics," Rosenberg said. "I don't care if he's a Republican. I don't care if he's a Democrat. I don't care if he's a senator. I don't care if he's a member of the House. I don't care if he's a state official. And I don't care if he's a local official. We believe he broke the law. That's why we brought the charges. Period. "

Bruce Alpert can be reached at bruce.alpert@newhouse.com or (202) 383-7861.